This invention relates to compounds having antiviral activity, pharmaceutical compositions thereof, and methods of treatment utilizing the compositions. In particular, this invention is related to compounds having antiviral activity against viruses of the herpes group, pharmaceutical compositions containing the compounds, and methods of treating viruses of the herpes group using the pharmaceutical compositions.
There are four separate viruses of the herpes group which infect and cause disease in humans. These are (1) herpes simplex virus 1 and 2 (HSV-1 and HSV-2, respectively); (2) cytomegalovirus (CMV); (3) varicellazoster virus (VZ); and (4) Epstein-Barr virus (EB). Examples of diseases associated with herpes simplex virus infection include herpes labialis, genital herpes (herpes progenitalis), neonatal herpes, herpetic keratitis, eczema herpeticum, disseminated herpes, occupational herpes, herpetic gingivostomatitis, meningitis (aseptic), and encephalitis.
CMV is widespread in humans and numerous other mammals. The great majority of human CMV infections are subclinical; that is, the primary infection occurs with no signs or symptoms. An exception to this is a congenital infection which occasionally gives rise to cytomegalic inclusion body disease in infants. There is also a mononucleosis-like syndrome caused by the virus.
The great majority of serious cases due to CMV infection come from recurring infections in immuno-compromised patients, such as transplant patients and cancer patients. It has been estimated that silent CMV infections have occurred in a majority of humans by the time adulthood is reached.
VZ virus is associated with chicken-pox (varicella) and shingles (zoster) in humans.
EB virus is quite common and causes glandular fever; it is also believed to cause the genetic damage that leads to Burkitt's lymphoma.
Examples of drugs used to treat herpes infections include: (1) IUDR (5'-iodo-2'-deoxyuridine); (2) Ara-C (1-[beta-D-arabinofuranosyl]-cytosine); (3) Ara-A (9-beta-D-arabinofuranosyladenine); and (4) Acyclovir (9-[(2-hydroxyethoxy)methyl]guanine). Also Haines et al. (U.S. Pat. No. 4,757,088 issued Jul. 12, 1988) disclose that lidocaine (2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide) is an antiviral agent in cell culture against HSV-1 and HSV-2, and is able to treat herpes virus infections of mammals. Haines et al. also disclose that lidocaine is particularly effective in the treatment of HSV oral and genital lesions in humans. According to Haines et al., the addition of pantothenic acid or its alcohol and salt forms, dexpanthenol and pantothenate respectively, to lidocaine or lidocaine hydrochloride significantly enhances the antiviral activity of those drugs.
In view of current interest in the art for finding useful antiviral agents, in particular, useful agents against herpes group viruses, any new compounds exhibiting antiviral activity would be a welcome contribution to the art. This invention provides such a contribution.